I think Polythene's suggestion is a great one. If you don't feel that you can manage a phonecall, would your partner or a friend be able to do it for you. I may talk the talk on here, but I have a habit of dissolving into tears at everything at the moment, so would probably be in the same boat as you.
You are going to be fine, and your baby is going to be fine. Yes, being overweight is not ideal, but neither is it the worst crime in the world. You're hardly puffing on a crack pipe and chugging vodka are you? As long as you doing your best to eat healthily and not mainlining sugar and rubbishy carbs, then you have nothing to worry about.
Some healthcare professionals really need to get to grips with the fact that not everyone with a higher BMIs are doughnut scoffing couch potatoes, it's such an ignorant and outdated view. My midwife looked really sceptical when I told her how much exercise I did and what I ate, I felt like showing her my cycle computer, my fitness pal, and pedometer app. Actually, maybe I will next time.